Page 161 - Physics_Form_2

Nature and reflection of light

Table 4.5
( f cm ) 1 (cm  1 ) ( u cm ) 1 (cm  1 ) ( v cm ) 1 (cm  1 ) 1  1 1   1

f u v f    u  v   cm

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Questions
(a) Describe the characteristics of the images for all object positions, using:
(i) a concave mirror
(ii) a convex mirror
(b) How do the measured image positions differ from the calculated image positions?
Give a brief explanation for any discrepancies.

This activity has revealed the Ensure that the image of the distant
characteristics of various images formed object is clearly visible.
by concave and convex mirrors. Although 2. Place the white screen on the bench
measurements of image and object and move it until a sharp image of
distances are affected by some errors, the the distant object is focused on the
values can be correctly approximated by screen.
using the mirror equation. Other image 3. Measure the distance between the
characteristics can also be predicted mirror and the screen. This distance
using the mirror equation. This verifies is the image distance, v, and it
the mirror equation.
approximately corresponds to the
focal length of the mirror.
Activity 4.11 4. Create a small round hole on one

Aim: To estimate the focal length side of the lamp box and attach the
of a concave mirror with an crosswire so that the crossing point
illuminated object. coincides with the centre of the hole.
Materials: concave mirror, metre rule, 5. Position the box on the bench outside
cross wires, lamp-box, the approximate focal length of the
mirror.
white screen, a V-stand, 6. Switch on the lamp in the box so that
bench, a source of light the crosswire is illuminated through
Procedure the box hole.
1. Fix the V-stand on a bench and 7. Move the screen until a clear inverted
mount the concave mirror on the image of the crosswire is formed on
stand so that the reflecting surface the screen.
of the mirror faces a distant object.

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Physics Form 2 Final.indd 155 25/10/2025 10:27